In the normal process of imparting twist to yarn, it is necessary that the speed of travel of the advancing yarn and the rotary speed of the twisting spindle be coordinated so that the twisting spindle is rotated at a predetermined ratio relative to the speed of travel of the advancing yarn. This twisting process requires a yarn conveying or withdrawing system which is driven at a definite speed, and a twisting spindle which is also driven at a definite speed relative to the speed of the advancing yarn. The speed ratio between the yarn conveying or advancing system and the twisting spindle may be adjustable and the two drive systems are operatively interconnected, either mechanically or electrically. However, the two separate drive systems and the interconnection therebetween add to the engineering and constructional cost involved in producing the twisting apparatus and is not necessary for certain uses of the twisting apparatus, as for example, disclosed in German Utility Model Gbm No. 84 05 365.
It is accordingly an object of the present invention to provide a yarn twisting apparatus which achieves a fixed ratio between the yarn withdrawal speed and the twisting spindle speed, and which imparts a definite and predetermined amount of twist (turns per meter) to the yarn.